Referrer Data Explained: Privacy-Friendly Analytics

Referrer data tells you where your visitors came from. It is one of the most valuable signals in your analytics dashboard — and it works the same way with cookieless analytics as it does with cookie-based tools.

What the referrer header contains

Every HTTP request a browser makes includes an optional Referer header (note: the HTTP spec misspells it — the correct English spelling is "referrer"). This header contains the URL of the page the visitor was on before navigating to your site.

When someone clicks a link on https://news.ycombinator.com/item?id=12345 that goes to your site, their browser sends:

Referer: https://news.ycombinator.com/item?id=12345

The analytics tracker reads this header and stores the referring domain (and sometimes path) with the pageview.

This mechanism requires no cookies. The browser sends the referrer header naturally with every navigation, completely independent of any tracking identifier.

"Direct / none" traffic explained

Direct traffic is pageviews with no referrer header. This includes:

Visitors who typed your URL directly into the address bar
Visitors who followed a bookmark
Visitors who arrived via an email link without UTM parameters (many email clients strip referrers)
Visitors who arrived from a mobile app
Visitors who arrived from a source that deliberately suppresses the referrer (rel="noreferrer" on a link)
Some HTTPS-to-HTTP transitions (referrer is stripped for security)

Direct traffic is not "unknown" traffic — it is traffic where the referrer header was absent. It often contains a mix of high-intent visitors (people who know your URL and type it directly) and traffic that is difficult to attribute.

Social referrers

Social media platforms send referrer headers, but with varying detail:

Twitter/X — sends t.co (their link shortener) as the referrer
LinkedIn — sends www.linkedin.com
Facebook — sends l.facebook.com or www.facebook.com
Reddit — sends www.reddit.com with path
Hacker News — sends news.ycombinator.com with path to the specific item

The item path for Hacker News referrers is particularly useful — you can see exactly which HN thread drove your traffic.

AI chatbot referrers

An emerging referrer category: AI chatbots. When ChatGPT, Claude, Perplexity, or similar tools provide a link to your site and a user clicks it, the referrer is typically the chatbot's domain.

This means you can see AI-driven traffic in your referrer breakdown as these tools grow. It appears as domains like chat.openai.com, claude.ai, or perplexity.ai.

UTM parameters and referrers

UTM parameters complement referrer data. While the referrer header shows which site sent traffic, UTM parameters show which specific campaign, post, or link within that site drove the visit.

If someone clicks a link in your newsletter, the referrer might be your email provider's redirect domain — or nothing at all (many email clients strip referrers). Adding ?utm_source=newsletter&utm_medium=email to your newsletter links gives you reliable attribution that does not depend on the referrer header.

See the UTM campaign tracking guide for how to set these up.

FAQ

Do referrers work without cookies? Yes. The referrer header is sent by the browser with every HTTP request, independent of cookies.

Why does my direct traffic seem high? Direct traffic includes email links, mobile apps, and bookmarks — not just typed URLs. It is often higher than people expect.

Can I see the full referring URL? Antlytics records the referring domain. Full path data depends on what the referring site sends.

Does HTTPS vs HTTP matter? Yes. When a visitor navigates from an HTTPS page to an HTTP page, browsers may strip the referrer for security. This is another reason to ensure your site uses HTTPS.